有关u-turn

小胡同

最近查google map for directions, 经常会看到需要u-turn。印象之中好像在主路上不可以，不管是否有不可u-turn的牌子。平常也看到有人在红绿灯处做u-turn。
请问u-turn到底是不是合法的？
  w9 e% s: d9 q' O谢谢！

EightBelow

U-turns
4 M: m% ^3 ~! W7 P• Do not make a U-turn unless you can do it safely and without interfering
+ T3 [9 \. D2 X" j) xwith other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
crest of a hill where the driver of another vehicle cannot see your vehicle.
2 ?  z' w# {8 s2 ?2 k1 _0 }U-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
9 z$ h0 p6 f7 B1 P2 @+ H& W# X8 H• Where a sign prohibits making a U-turn.
1 Q! }! \  {. c  k8 S- Z• At an intersection controlled by a traffic-control signal (traffic lights).
• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。